1. Field of the Invention
This invention relates to increasing electronic device cooling, and more particularly to a method and apparatus for providing fan redundancy.
2. Description of the Related Art
As electronic devices, such as microprocessors, central processing units (CPUs), servers, and other similar types of electronic components become faster and are reduced in size, power consumed within the system per unit volume (power density) increases dramatically. Therefore, it is essential to dissipate the heat generated by electronic components within the system during its operation to keep the electronic components within their normal operating temperature ranges. If the electronic components operate outside of their operating temperature ranges, the life span of the electronic components will be reduced or fail immediately.
One effective technique for dissipating the heat from electronic components, such as a microprocessor, is to provide an internal fan, or fan assembly, to directly apply a relatively high-velocity air stream across the surface of the electronic components. By forcing high-velocity air across the surface of the internal component(s), the conductive heat transfer coefficient for the surface of the internal electronic components is increased, thus increasing the convection cooling. Another technique of dissipating the heat from an electronic component, such as a microprocessor CPU, is associating a heat sink with the microprocessor CPU to increase the heat-dissipating surface area of the CPU for more effective cooling. These heat sinks have multiple heat-dissipating fins or elements at an upper surface. A lower surface of the heat sink is coupled to the electronic component and attached with a retention clip. Since the heat sink is comprised of metal or metal alloys, the heat sink conducts heat away from the microprocessor CPU and allows convection cooling through the fins.
One method to achieve cooling on devices such as microprocessors is to add additional fans by placing fans in parallel and in series. A problem with this method of cooling is that if one fan fails, the remaining fan must force air through an inoperable fan. Upon forcing air through an inoperable fan, fan speed must be increased, which significantly increases noise and limits the types of fans that can be used. Single point failures often occur in motors, fans and mechanical devices. Many times, a bearing is the source of the single point failure. When a bearing fails in a fan, the motor or electronics subsequently fail.